An IT technician must upgrade all the PCs in an office by adding 256 MB of RAM to each machine and replacing the CPUs with a Dual Core processor.
A supplier will provide twelve Dual Core processor chip and 2048 MB of RAM for £1200 or nine Dual Core processor chip and 2560 MB of RAM for £960.
By using Determinant, matrices (inverse matrix) and Graphical methods, find how much does the supplier charges for a single Dual Core processor chip and for a single piece of 256 MB RAM. (P1, P2, P5)

Cheers,
~Bckc

Apr 24th 2012, 03:27 PM

HallsofIvy

Re: PLease help, matrices

Let x be the total number of lots of "twelve Dual Core processor chip and 2048 MB of RAM" ordered and let y be the total number of lots of "nine Dual Core processor chip and 2560 MB of RAM" ordered. Then the total number of Dual Core processor chips ordered is 12x+ 9y and total RAM ordered is 2048x+ 2560y. The cost will be 1200x+ 960y. You can write that information as
$\displaystyle \begin{bmatrix}12 & 9 \\ 2048 & 2560 \\ 1200 & 960\end{bmatrix}\begin{bmatrix}x \\ y\end{bmatrix}= \begin{bmatrix}P \\ M \\ C\end{bmatrix}$
where "P" is the number of processor chips, "M" is the memory in MB of RAM and C is the cost.

What must x and y be so that P= 1 and M= 0? What is C in that case?
What must x and y be so that P= 0 and M= 256? What is C in that case?